I updated the forums yesterday to the latest version of the vBulletin software, v3.8. It has a bunch of new features, including social groups, new private message filtering/sorting options, and so on. See the full list here:
Until I get some skins for the forums, I've set everyone to be using the default. If you see a vBulletin forum skin you like that is compatible with v3.8, let me know.